For a considerable period of time, industry has relied upon a concept for preventative maintenance which is based upon the detection, analysis and correction of vibration in monitored machinery. Initially, periodic vibration measurements were made at various locations upon industrial machinery to detect an increase in vibration which represented that machine deterioration was at hand. An analysis of vibration was found to provide information which could indicate what trouble was at hand so that proper corrective action would be taken. This general concept of preventative maintenance has grown considerably to the extent that vibration monitors now are permanently installed upon critical machines to provide continuous vibration output signals.
The varieties of vibration monitors vary considerably in capability and complexity, however, all seek the avoidance of catastrophic breakdown through techniques wherein operating personnel are given as much information concerning machine condition as is practical. As might be expected, as the number of positions upon machinery being monitored by transducers, referred to as "channels," as well as the number of machines being monitored increases, so also do the number of visual readout devices increase. Thus, operators and maintenance personnel are called upon to devote a considerable amount of time and effort in operating the monitoring devices themselves, and such efforts are quite important. Further, the number of electrical and electronic components within each of many channels has become significant in terms of cost.
Generally, limits for the values of vibration parameters are predetermined such that conditions representing a warning of imminent malfunction may be known and, in many installations, "trip" or "warning" levels are established. For the latter conditions, relays or the like are actuated automatically to shut down respectively the monitored machinery or energize a perceptible indicator. As is apparent, it is desirable to apprise operating personnel of the status of all monitored positions in as simple and thus efficient a manner as possible. To the present, separate meter readings at each monitoring station or channel are taken by the operators, these readings are then mentally compared with pre-designated warning or trip levels and a mental determination is made as to whether further corrective action should be taken. Of course, the mental steps involved in this procedure represent a potential error factor as well as one representing the consumption of operator time.
Because the shutdown of monitored machinery represents an undesirable loss of production, the tampering with preset trip levels by personnel can be contemplated. To discourage such tampering, potentiometers or like adjustable devices setting such limits with respect to each monitoring channel have been positioned at relatively inaccessible locations. For example, portions of the monitoring equipment may have to be removed in order to achieve access to the adjusting devices. While enhancing the security of the monitoring devices, such inaccessibility has represented an obvious inconvenience.